make poll_join_next pub and add reset_after fns

msim/src/sim/task/join_set.rs

@@ -94,7 +94,7 @@ impl<T: 'static> JoinSet<T> {
         std::mem::swap(&mut new_inner, &mut self.inner);
     }
 
-    fn poll_join_next(&mut self, cx: &mut Context<'_>) -> Poll<Option<Result<T, JoinError>>> {
+    pub fn poll_join_next(&mut self, cx: &mut Context<'_>) -> Poll<Option<Result<T, JoinError>>> {
         let pinned = Pin::new(&mut self.inner);
         pinned.poll_next(cx)
     }

msim/src/sim/time/interval.rs

@@ -171,6 +171,13 @@ impl Interval {
         self.delay.as_mut().reset(Instant::now() + self.period);
     }
 
+    /// Resets the interval after the specified [`std::time::Duration`]
+    ///
+    /// This method ignores [`MissedTickBehavior`] strategy.
+    pub fn reset_after(&mut self, after: Duration) {
+        self.delay.as_mut().reset(Instant::now() + after);
+    }
+
     /// Returns the [`MissedTickBehavior`] strategy currently being used.
     pub fn missed_tick_behavior(&self) -> MissedTickBehavior {
         self.missed_tick_behavior